1. Field of the Invention
The present invention relates to wireless communication, and in particular, to a mobile communication device for multimode communications and an integrated circuit thereof.
2. Description of the Related Art
Fourth generation (4G) communication technologies such as Long-Term Evolution (LTE), LTE-Advanced, and Worldwide Interoperability for Microwave Access (WiMAX) communication networks are packet-switched networks, which provide high-speed data services through Multiple Input Multiple Output (MIMO) technology, a multi-antenna technology which provides various modes of transmit diversity, large delay Cyclic Delay Diversity (CDD), multi-user MIMO and closed loop spatial multiplexing.
While the 4G communication technologies offer enhanced data throughput, legacy communication technologies such as second generation (2G) and third generation (3G) communication technologies are still in use due to their wider radio coverage. Therefore mobile phones supporting multimode communications such as 4G/2G or 4G/3G or 4G/3G/2G communications are in need.
Currently the multimode communications for the 4G and legacy communication technologies are provided by network operators by either simultaneous Voice and 4G (for example, SVLTE—simultaneous voice and LTE) or Circuit Switched Fall Back (CSFB). Both approaches require considerable efforts and costs from the network operators to upgrade the multimode communication supports into the network.